Rheostat.



R. E. NUBL & L. E. MITCHELL. RHEOSTAT.

APPLICATION PVILED PEB. 5, 1909.

929,001 Patented July 2'?, 1909.

2 SHEETS-SHEET 1.

WITNESSES: INVENTUHS R. E. NOBLE 6L L. E. MITCHELL.

RHEOSTAT.

AlPLIcATIoN FILED m15. 1909.l

929,001, f Patented July 27, '1909.

Z SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.`

RALPH E. NOBLE AND LOUIs E. MITCHELL, or CHICA GO, ILLINOIS, AssieNoRs To MORGAN- CARDNER ELECTRIC COMPANY, F CHICAGO, ILLINoIs.

RBEOSTAT.

Application 'med February's 1909.v serialize. 476,191.

To all whom it may concern' `United States, residing at Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Itheostats, of which the following is a speci-1l iication.

Tlus Inventlon relates to rheostats or resistance ada ted to be used 1n connection with Control ing electric currents and more ,cned or widened forked bearings 11 at theA particularly with strong currents, such, for instance, .as used in connection with street railway cars, locomotives, or the like.| Such rheostats, in order to serve their purposes most fully, should not only be able to take care f the large current, which they are intended. to regulate, without injury t0 the resisting grids yor members, but should also be amply ventilated, in order to allw for the escape of the heat generated therein; should be rigid and substantial in construction; and should have the varilousfpartsso arranged that repairs may be easily made. Many of these 'features' are lacking, to a greater, Or less extent, fin rheostats which havebeen in Zuse heretofore.

The objects of the present invention are to provide a rheostat embodyingthe desirable features abovernentioned, and also one in which the parts are comparatively f ew in number, of a simple construction, and which may be readily assembled to form the complete device.

In the accompanyingdrawings, showing a rheostat embodying our invention-Figure 1 is a detail sectional view showing .portions of two sets of gridswith their coni necting devices; Fig.2 isa iront view of the complete rheostat, with. one of the front doors, or grates removed to show the interior construction; Fig. 3 is a sectionalview. on the line 3 3 of Fig. 1 and Figs-V1 and 5 are details showing the wire terminals and 1 'grid members.

connectors for making connections with the these drawings, `6 represents Vva rack or'franie of sufficient sine to hold the @desired number OfA grid sections.

In the present instance, this frame is shown with 1 a central wall or division 7, in order to form two-.compartments for the grids or resistance l ing washers 15 are 1 venience inconstruction, and in making the Be 1t. known` that we, RALPH' E.NOBLE and LOUIS E. MITCHELL, citizens of thedesired electric circuits, the-grids proper 19 Patented Ju'ly 27, 1909.

are preferably arrangedin a plurality of sec- I :tions or piles. These grids are formed of some suitable material adapted to give the gnecessaryresistance and are usually cast iso `as t0. give an elongated-circuit in each grid, 'als indicated in Fig. 3. In order to sup# port these rids sov that they will :be comparatively ree from vibration and injury from jarring, they. are provided with thicklends thereof and U-shaped bearin s 12 at ranged in a vertical plane'at about the centers 'bf the grids, so as to give as little o portunity for vibration as possible. hese bearings rest on insulating tubes 13 mounted 0n rods or bolts 14 .which extend somewhat beyond the ends of such tubes.'

In Order to make roper circuits, insulataced between the bearings or` hubs 11, where it isdesired to pre- .vent thecurrent from passing immediately from one4 hub to another, these washers orthe centers thereof, these bearings eing ardinarily being placed between each alternate -set f'hubs, as indicated in Fig 1. In order l t0 bind the hubs or bearin s tightly together' to prevent movement of t e saine and to insure goodA electrical contact between the hubs-which carry the current from one grid to another, we provide insulating Washers 16 which fit over the ends of the insulating tubes 13 and restv against the adjacent hubs or connectors and which'are in turn engaged by countersunk washers Or ea s 17 which are pressed inwardly by means o nuts 18,011 the threaded ends of the bolts 14. In order to prevent these nuts from becoming loosened, and also in Order to take up any slack ,or looseness between the grid hubs or washers after the same have been in` use, we provide spring' nut lo'cks 19 which are inserted be'- tween thenuts 18 and the washers 0rc'aps 17. When the desired lnumber of grids .are thus secured together, they will be held firmly and rigidly, andthe arrangement is such that the parts wi'll b e securel' united regardless of slight in ccuracieso the sizes of the grid .membersz "The' grids thus connectedtogether form units or sections', apluraljty of bolts Orrods 14"engage with holes in the' leo . slid into place in the frame.

resistance su ports 9, these supports being rovided Wit openings or recesses 2O which t over the nuts 18 and also over spacing nuts 21, these openings conforming 'with the shape of the nuts, so that when the supports are in-v position, the nuts will be prei/entel from turning. Alfter the grid sec-tio. s or units have been tightly clamped together by means of the nuts 1S, the spacing nuts 2l on the threaded ends of the rods le are turned to the proper position to engage 'with the bottoms'of therecesses 20 to hold the supports 9 inv suitable position to closely with the slideways 8 in the frame 6. The

supports 9 arethen placed in position on the ro( 14 and then the entire unit or section The supports 9 are provided with lugs 22 which are ada ted to engage with the front edges of the si( es of the frame 6 in order to aline the supports in the frame. l/Vhen all of the sections have been inserted in osition, the front grate or door 28 is placed. 1n position,the edges oil this door engaging With the ends of the supports 9, thereby holding them in the frame.

ln order to make the desired connections between the banks or units of grids at the center `of the rheostat, We provide connections 2d, one end of such connections being in the form of an eye for engagement with the insulating tube 13 Ato connection With the hubs or bearings l1, and the other end being in the form of a hook. Electrical connection between these hookedeends is made by means of belts 25 and spacing pipes 26, as indicated in Figs. l and 2, the hooks on the connectors 24 being pressed into en gagement with the pipes 2G by means of nuts 27 en the bolts 25. w

In order torprovide terminals for connections with the Wires leading to the source of electric supply and to the' motors, other con-I nections 28,. preferably of the saine form as the connections 24, are inserted at the outer ends of the banks or series o grids, as indicated in lFig. 1,- these connections also having hooked ends between which the circuit 1s completed by means of links 29 and 30'.

, The link 29 is provided with a stud 3l, as indicated in Fig. 4, for engagement with the end of the lower lconnection 28 and is held in position by means of a nut 32 which en gages with the threaded end of the stndand presses' against a spring washer 33 which rests against the hooked end of the connecu tion 28. The link 3() is provided with a hole Ain the end thereof, corres ending in shape to the nut 32, so that this ink maybe used for screwing u the n ut and, when all of the arts are ina'y adjusted, serves as a lock ier said nut. rlhe terminal proper 34 is rovided at its inner end with a stud 35 'vv ich engages with the ends ofthe links 29 and 30 and with the hooked end of the up er connection 28. This stud is threads. on its rovided With a lic-le 38 into which grids', such series may be readily slipped out of the'casing, When the door is removed, for the purpose oi' adjustment or repairs. T hen, `if desired, the supports 9 maybe removed, allowing the nuts i8 to be loosened, and when thesey nuts are loosened, any broken or detective grid may be raised out of itsposition without interfering with the other grids. Vilhen a .newv grid is inserted, the nuts may again be tightened Without disarranging the spacing nuts 21. When the parts have been again placed into position, and the doers closed, the rheostat is ready .for use; and, en account oit' the arrangement whereby nearly all of the nuts a locked, none of thel parts are'apt to. be readily loosened.

Having thus described our invention which We do not Wish to limit to the exact construction or arrangement'sliown and described, what we claim and desire to secure by Letters Patent is:

l. ln a rheostat, the combination of a rack or frame, slideways in said frame, slides adapted to engage With said slideways, and a plurality oi' resistance grids mounted in said slides.

2. ln a rheostat, tbe combination oi' a frame, slideivays in said vtrame, grid resistance supports slidably engaging with said slideways, cross-rods engaging Wit/h, said supports, a plurality of resistance grids or members mounted on said cross-r`ods, and means coacting with s reds vier clamping said grids independently of said supports.

.3. In a rhsostat, the combination of a rod, an insulating tube on said rod, a plurality of resistance members engaging with said tube, caps at the oi' said red adapted to'prof y tect the insulating tube, and means for pressev ing said caps longitudinally oi said-rod for clamping the resistance members together..

4. The combination of a'rod, an insulatingtube on said rod, a plurality of resistance' members engaging with said tube and adapt-.

ed to be supported thereby, insulating Wash' ers on the ends of said tube, caps on said rod for protecting the ends ofs'aidtube and for or was ers engagin yielding'nnt locks, for the urpose'desoribed. 5. Ina devic'eof the c aracter set forth,

the combination of a plurality of rods vor bolts, insulating tubes engaging with said rods, a lurality of resistance members having hu s or bearings 'engaging with said tubes, insulating Washers arranged between some of said hubs and at the ends o1 said tubes, cas at 'the ends of said tubes for pressing t ehubs and washers together, nuts on said rods for tightening said caps,spacing nuts at the ends of said rods, and supports engaging with said rods, said supports having recesses for receiving s aidnuts and preventing them from turning, the position of said supports being also determined by said spacing nuts.

6.'Inv a rheostat, the combination of a frame, a plurality of grid resistance supports slidably mounted in said frame, and doors engaging With said supports for holding them in position.

7. In a rheostat, the combination of a frame, a division Wall in said frame, slideways in the divisions thus formed, a plurality of resistance grids mounted in said slideways, electrical connectors engaging with the grids adjacent to the division wall, having hooked ends, and rods orbolts engaging with said hooked ends for furnishing 'electrical connection between the banks of vgrids in the separate divisions.

8. n a rheostat, the combination of a frame or casing, banks of resistance grids mounted in said casing, connections for making contact with some of said grids, a link having a stud at one end for engagement with one of said connections, a nuton said stud, a second link having an opening in the end for engagement With said nut, and a terminal connection having a stud engaging with the oppov site ends of said links and with the other connectiOn, whereby an electric circuit is made 10. The combination with grid resistance u supporting rods having nuts at the ends thereof, of supporting members adapted to engage With said rods and with? said nuts, said members being provided with recesses corres ending With the shape of said nuts, where y .such members may be used as Wrenches for. turning the nuts and will also serve to hold the nuts in position when the rods are in engagement with said members'.

. RALPH E. NOBLE.

. LOUIS E. MITCHELL. VVitness'es: WILLIAM A. NARTEN, B. P. TRACY. 

